Method and receptacles for growing plants, particularly tissue culture plant precursors

ABSTRACT

A method of growing tissue culture callus on a nutrient substrate comprises the steps of preparing a semi-solid slab of the nutrient substrate and placing it on top of a honeycomb-like forming plate, which defines a plurality of hollow passages surrounded by thin walls. A series of the callus is deployed on the slab, so that each callus is located in alignment with one of the passages. The callus are allowed to grow to a desired extent under conventional conditions. A pneumatic pressure is then applied to the slab so that it becomes pushed through and sliced by the walls of the forming plate into a respective number of blocks, each carrying a single plant, and ejected out of the bottom side of the forming plate for further plantation thereof.

This is a division of application Ser. No. 08/097,664, filed Jul. 27,1993, now U.S. Pat. No. 5,425,202.

BACKGROUND OF THE INVENTION

The present invention relates to breeding of plants and moreparticularly to plants breeding based on tissue culture cells or callus(hereinafter referred to as "callus") which are allowed to develop on anutrient substrate, generally known as agar-agar.

The development of plant precursor on agar-agar base has rapidlyincreased, since found as the most effective way of plant cultivation,particularly due to the high yield (plants per area unit) that can bereached--in contradistinction to soil seed growing methods.

However, such callus growing, under laboratory conditions, usually intest-tubes, bottles or similar containers, is disagreeable from thefollowing aspects: The development of a plant, by its very nature,suffers if its surrounding is confined by partitions of any kind(impeding free growth in all directions; the "shadowing effect" of suchpartitions; and finally, the need to apply mechanical means (by the useof tweezers and the like) for extracting the plant for furthercultivation thereof, usually re-planting thereof in seedling ortransplantation trays. It is well-known that plants, at this early stageof their life, are most vulnerable so that transportation from oneenvironment to another could be traumatic and therefore must be carriedout with utmost care.

Various attempts have been proposed to partly solve this problem (seefor example U.S. Pat. No. 4,620,390 to the present Applicant which isbrought as general background).

It is thus the general object of the invention to provide a method ofplants development ensuring, on the one hand, the free and unimpededdevelopment of the callus in all directions and, on the other hand, thequick, convenient and least harmful translocation of the plants.

It is a further object of the invention to provide a method whereby thehandling of the plants is effected without human touch, and which isreadily performed by automatic means.

It is a still further object of the invention to provide a receptaclereadily useful for carrying out the method of the present invention.

SUMMARY OF THE INVENTION

According to one, general aspect of the present invention there isprovided a method of growing plants, particularly tissue culture callusgrown on a nutrient substrate such as agar-agar. A semi-solid slab ofthe nutrient substrate is prepared and placed on top of a honeycomb-likeforming plate, which defines a plurality of hollow passages surroundedby thin walls. A series of the callus is deployed on the slab, so thateach callus is located in alignment with one of the passages. The callusare allowed to grow to a desired extent under conventional conditions. Apneumatic pressure is applied to the slab so that it becomes pushedthrough and sliced by the said walls into a respective number of blocks,each carrying a plant. The blocks are ejected out of the bottom side ofthe forming plate for further growing of the plants.

According to another aspect of the invention there is provided anassembly for growing plants, particularly tissue culture callus grown ona nutrient substrate such as agar-agar. The receptacle comprises abottom tray, a forming plate comprising a honeycomb-like structuredefining a plurality of hollow passages surrounded by thin walls andhaving a circumferential top and bottom frame walls. The bottom framewall is configured to tightly fit into the bottom tray. A semi-rigidslab of a nutrient substrate is placed over the forming plate. Atransparent cover tray is provided which fits over the forming plate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further aspects, advantages and features of the invention willbecome more clearly understood in the light of the ensuing descriptionof a preferred embodiment of the invention, given by way of exampleonly, with reference to the accompanying drawings, wherein:

FIG. 1 is a three-dimensional, exploded view of the main components of areceptacle applicable for carrying out the method according to thepresent invention;

FIG. 2 is an elevation of the cellular forming plate shown in FIG. 1;

FIG. 3 is a partly cross-sectional view illustrating the stage ofpreparing a nutrient substrate slab with the forming plate partlyembedded therein;

FIG. 4 illustrates a stage prior to the distribution of living matter,e.g. plant callus over the nutrient material slab;

FIG. 5 illustrates a specifically designed strainer plate useful incarrying out the method according to the invention;

FIG. 6 illustrates the manner of spreading individual living materialcallus over the strainer plate;

FIG. 7 shows, on an enlarged scale, a construction detail of thestrainer plate;

FIG. 8 illustrates the stage of transforming the living material callusover the nutrient substrate slab;

FIG. 9 illustrates at its right hand side, the planted living mattercallus, and at its left hand side, plants at their final developedstage;

FIGS. 10a and 10b illustrate the slicing stage of the nutrient substrateslab; and

FIG. 11 illustrates the manner of ejecting individual plants togetherwith their associated blocks of the slab, for further processing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1 the receptacle useful for the method providedaccording to the invention comprises a pan like tray 10, a honeycomb- orgrid-like forming plate generally denoted 12, and a transparent covertray designated 14. As shown, the base tray 10 is rectangular, althoughany other shape may be used as the requirements may dictate. The tray 10has a bottom wall 16. Four side walls 18a, 18b, 18c and 18d are present,tapering outwardly to conform to complementary walls of the formingplate 12 as will be described now.

The forming plate 12 is rectangular, conforming to the dimensions of thetray 10, and comprises a grid structure defining cells or passages 20 ofsquare cross-section. Again various other cross-sectional shapes maybecome useful. The passages 20 are divided by a lattice work of thinwalls which preferably taper from bottom to top, ending with almostknife-edge lips 20' at the top side thereof. The plate is surrounded byfour downwards convergent tapering circumferential bottom frame walls22a-22d, four upwards convergent circumferential frame walls 24a-24d,and a girdle 26. The girdle may be continuous, or include various shapedsections. The frame walls 22 snugly fit into the open top of the basetray 10. Finally, the cover 14 fits over the walls 24, is necessarilytransparent and of a sufficient height to make room for the growth oftissue culture callus as known in the art.

Turning now to FIG. 3 the stage of preparing a nutrient substrate slabfor the planting of the live material callus is illustrated. As known,the nutrient substrate material ("agar-agar") is prepared from asolution of water and filler substances including minerals and othernutrient components necessary for the plant, which is molded into asuitable shape and allowed to solidify at room temperature to form ajelly like material.

According to one of the unique features of the invention, an agar-agarjelled slab, denoted 30, is prepared within a molding tray 32 which fitsover the top frame wall 24 of the forming plate 12. Hence, theagar-agar, in liquid form, is poured into the tray 32 and the plate 12is placed thereover so that the top, knife-edged lips 20' of thepassages 20 are partly immersed and thus become embedded in the materialof the slab after it solidifies. However, as will be explained later,this association between the forming plate 12 and the slab 30 is merelyoptional and the method provided according to the present invention canbe put into practice without this feature.

After the solidification of the slab 30 and removal of the tray 32, thearray comprised of the forming plate 12 with associated slab 30 and thebottom tray 10 is placed upside-down, as shown in FIG. 4.

Turning now to FIGS. 5, 6 and 7, there is shown a sift or strainer plategenerally denoted 40 specially designed for facilitating thedistribution or deploying of individual live matter bodies over the slab30 in a predetermined, matrix arrangement, namely so that each bodybecomes located exactly over and in register with the center of each ofthe passages 20.

Thus, the plate 40 comprises a matrix of small depressions or recessesdenoted 42 as most clearly shown in FIG. 7, extended by a draining or adropping opening 44, preferably cross-shaped. Further provided is ahandle portion 46 and eight location pins 48, each pair of location pinsprotrude from the side of the depressions extending at the four cornersof the strainer plate 40, the arrangement being such that when the plate40 is placed over the forming plate 12 all the depressions 42 becomelocated in alignment with a central axis of the respective passages 20,as well as at a certain distance S above the slab 30--as clearly shownin FIG. 8.

The process of placing individual living material callus into thedepressions 42 is illustrated in FIG. 6 and performed in the followingmanner. There is prepared a container 50 filled with a liquid 52 whereinindividual live material callus 54 are distributed and hold insuspension. Now, by passing the plate 40 through the liquid 52 inupwards movement, as denoted by the arrow 56, callus 54 are individually"fished" and become entrapped within the depressions 42 (see in FIG. 7).

A similar result can be achieved by pouring a liquid suspension such as52 over and through the strainer plate 40.

The strainer plate 40, charged with the callus 54 (although some of thedepressions 42 may be left vacant), must now be loaded onto the slab 30.For this purpose the assembly of the bottom tray 10 and the formingplate 12 (FIG. 4) is placed in an upside-down position over the strainerplate 40 (not shown), and then turned over together back into theposition shown in FIG. 8. Removal of the strainer plate 40 will leavethe callus 54 lying on the slab 30 as shown in FIG. 9. A furtheroperation of stucking the callus 54 partly into the material of the slab30 may be necessary and manually performed with a suitable tool (notshown).

The transparent cover plate 14 is now placed over the forming plate 12and the plants are allowed a grow up to a suitable size (about 10 mm) asdesignated 56 in the left hand side of FIG. 9.

In order to remove the plants 56 out of the receptacle for the followingtransplantation thereof, say into conventional plantation trays, theprocess illustrated in FIG. 10a and 10b is performed. The forming plate12 is placed over a base 60 after its removed from the base tray 10. Thetop surface of the base 60 is preferably made rough to allow the ventingof air (see below). An additional cover tray 62, with air pressurefitting 64, is placed tightly over the upper frame walls 24 of the plate12 and preferably clamped thereto by a pivoted hook member 66.

Now, by applying sufficient air pressure into the cover tray 62, theslab 30 functions as a "plunger" and becomes pushed downwards as aunitary body, causing thereby the gradual slicing thereof by the edges20' of the respective passages 20. The slab thus becomes divided intosquare blocks 70, each ultimately seated against the base 60 at thebottom side of the tray 12, including its respective plant 56 (see FIG.10b).

The system is now ready for the final stage of ejecting the blocks 70outwards through the open bottom of each passage 20. This operation canbe performed by again using air pressure delivered through one or morenipples 72 fitting into the top of passage(s) 20.

It will be readily appreciated that the plants 56 may be now furtherprocessed, by automated machinery (not shown), directing each and everyblock 70 into a respective compartment of a conventional transplantationtray 74 moving in the X-Y directions as schematically illustrated inFIG. 11.

It has been thus shown that by relatively simple and straightforwardequipment, an advantageous method is provided, ensuring a convenient,quick and effective live tissue growing of plants which, on the onehand, guarantees minimum traumatic damage to the so sensitive tinyplants at the end of their development, and on the other hand, isreadily applicable for following processing and handling techniques.

Those skilled in the art will readily appreciate that numerous changes,variations and modifications may be applied to the invention asheretofore exemplified without departing from the scope thereof asdefined in and by the appended claims.

What is claimed is:
 1. An assembly for growing plants, particularlytissue culture callus grown on a nutrient substrate such as agar-agar,the assembly comprising:a bottom tray, a forming plate comprising ahoneycomb-like structure defining a plurality of hollow passagessurrounded by thin walls and having circumferential top and bottom frameside walls, the bottom frame wall being configured to tightly fit intothe said bottom tray, a semi-rigid slab of a nutrient substrate placedover the forming plate, and a transparent cover tray, configured to fitover the circumferential top frame side wall of the forming plate,wherein a top portion of the forming plate is partly embedded in thesaid semi-rigid slab.
 2. The assembly as claimed in claim 1 wherein thewalls of the passages of the forming plate taper convergently toward atop side thereof.
 3. The assembly as claimed in claim 2 wherein theforming plate includes a girdle projecting outwards, extending betweenthe said circumferential top and bottom frame side walls.